Enzymatic resolution, desymmetrization, and dynamic kinetic asymmetric transformation of 1,3-cycloalkanediols
An efficient desymmetrization of cis-1,3-cyclohexanediol to (1S,3R)-3-(acetoxy)-1-cyclohexanol ((R,S)-2a) was performed via Candida antarctica lipase B (CALB)-catalyzed transesterification, in high yield (up to 93%) and excellent enantioselectivity (ee's
Rhodium(I)- and iridium(I)-catalyzed hydroboration reactions: Scope and synthetic applications
A study of the rhodium(I)- and iridium(I)-catalyzed hydroboration of olefins with catecholborane is described. Applications to organic synthesis were one focus of this investigation. The scope of the reaction was defined, and issues of stereoselection were addressed. The rhodium-catalyzed hydroboration of several classes of allylic alcohols was found to be highly diastereoselective, preferentially affording the isomer complementary to that furnished by the uncatalyzed variant of the reaction (9-BBN). The first two general approaches to effecting a directed olefin hydroboration were developed. Both phosphinites and amides proved capable of delivering the transition metal reagent.
Evans, David A.,Fu, Gregory C.,Hoveyda, Amir H.
p. 6671 - 6679
(2007/10/02)
Rhodium(I)-Catalyzed Hydroboration of Olefins. The Documentation of Regio- and Stereochemical Control in Cyclic and Acyclic Systems